Allow attributes on parameters and return values

Any annotation where the key has a dot in the name will go into the
attribute list. For example

  * @arg: (foo.bar baz): some arg

the parameter @arg will get the attribute with key foo.bar and value
baz. This also works for.

  * Returns: (foo.bar2 baz2): the return value

Also add tests for this new feature.

See https://bugzilla.gnome.org/show_bug.cgi?id=571548

Signed-off-by: David Zeuthen <davidz@redhat.com>

gitypelib-internal.h

@@ -1110,6 +1110,10 @@ gboolean g_typelib_validate (GTypelib  *typelib,
 			     GError    **error);
 
 
+/* defined in gibaseinfo.c */
+AttributeBlob *_attribute_blob_find_first (GIBaseInfo *info,
+                                           guint32     blob_offset);
+
 G_END_DECLS
 
 #endif  /* __G_TYPELIB_H__ */